let menu = {
    width: 200,
    height: 300,
    title: "My menu",
};

multiplyNumeric(menu);

for (let key in menu) {
    alert(menu[key]);
}


function multiplyNumeric(obj) {
    for (let key in obj) {
        if (typeof(obj[key]) == 'string') {
            continue;
        } else {
            obj[key] *= 2;
        }
    }
}